How do I beat moderate AI with fast castle?

I've been playing as the Huns, get to castle age in 19:30-20:30 minutes usually. How do I improve this time? I see people doing a fast castle in 18 minutes... I usually get 25-30 villagers, lure boar, etc. I've been using build orders that I've seen online and I usually put up somewhat of a fight early on, but always get outnumbered. Is out-rushing the AI just impossible if you're not a pro?

For those wondering, I'm trying a knight/cav archer rush. Neither seem to work. Got it to work against standard AI fairly easily. Moderate AI is just another level.